I am using Telegram Desktop 0.8. I am connecting to the internet via an authenticated proxy. Telegram will not connect with such connection. How to configure it properly? Just open Settings > scroll down > Advanced > Connection type.

Find The Configuration

HTTP Proxy

The most common proxy is HTTP. If it is yours, then check HTTP with custom http-proxy. It works with HTTPS too.

HTTP/HTTPS

SOCKS Proxy

If your proxy connection based on SOCKS, then check TCP with custom socks5-proxy.